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Vibration Isolation of Precision Payloads: A Six-Axis Electromagnetic Relaxation Isolator

This paper describes a passive six-axis vibration isolation system for space applications. The system consists of a Stewart platform with cubic architecture; each leg is equipped with an electromagnetic transducer connected to a RL circuit. The system behaves like a relaxation isolator and its transmissibility exhibits an asymptotic decay rate of ―40 dB/decade. The performances are very similar to that of an active isolator based on a skyhook controller.

SAM : A 7-DOF portable arm exoskeleton with local joint control

This paper presents the development of SAM, the Sensoric Arm Master, a 7-DOF portable exoskeleton with integrated actuation and sensors. Local joint control is implemented to improve performances of the device. Some experiments have been conducted with the system to show the functionality of the exoskeleton device linked to a virtual reality.

Computer Controlled Rotational MR-brake for Wrist Rehabilitation Device

This aricle presents a novel, computer controlled, magneto-rheological (MR) brake actuated, muscular rehabilitation, and evaluation device. The first part discusses various MR brake architectures and compares them. Simple analytical formulae are developed for a set of figures of merit, which point out the role played by the various parameters. Based on this analysis, a prototype with a T-shaped rotor has been designed, built and integrated into a portable rehabilitation device. In the second part of the article, the various exercise modes of the device and its control are described. Finally, results validating the performances of the device for the pronation/supination motion of the wrist are shown.

On magnetorheologic elastomers for vibration isolation, damping, and stress reduction in mass-varying structures

This article considers two devices based on a magnetorheological elastomer (MRE): an MRE isolator under a frequency-varying harmonic excitation and a MRE Dynamic Vibration Absorber (DVA) mounted on a frequency-varying structure under a random excitation. In the first case, it is shown that the commandability of the elastomer improves the reduction of the RMS value of the body displacement by 10%. In the second case, it is shown on a simple example that a MRE DVA, while not optimal, can reduce the stress in the structure about 50% better than a classical DVA when the mass of the structure changes 35%. This makes them suitable to avoid high stress in mass-varying structures, and delay some damage mechanisms like the emergence of cracks and fatigue.

Isolation and damping properties of magnetorheologic elastomers

This paper considers two systems based on a magnetorheological elastomer (MRE): a MRE isolator under a frequency varying harmonic excitation and a MRE Dynamic Vibration Absorber (DVA) mounted on a frequency-varying structure under a random excitation. It is shown that the commandability of the elastomer improves the isolation performances in the first case, and decreases the stress level in the structure in the second case.

Portable smart wrist rehabilitation device driven by rotational MR-fluid brake actuator for telemedecine applications

This paper reports on the current status of the effort conducted at ULB in order to develop a portable muscular rehabilitation device for telemedicine applications. It is divided into four parts. The first part recalls the basic modes of muscular rehabilitation and gives a brief overview of commercial rehabilitation machines as well as portable devices under development. The second part describes the design of the proposed device and justifies the selection of MR-fluid brake actuation. The third part is devoted to the description of the control strategies implemented on the device. Finally, the last part describes preliminary results obtained with the device for the various exercise modes.

MR-Tech: A portable smart wrist rehabilitation device

The purpose of this paper is to present a novel patent-pending, computer controlled, MR-brake actuated, muscular rehabilitation and evaluation device that can be carried to and used at patients home (without the immediate assistance of the physiotherapist), offering similar functionalities as existing stationary devices that can be found in hospitals (i.e. isometric, isotonic and isokinetic exercise modes). The first part of the paper describes in more details these various exercise modes. The second part is devoted to the design of the machine and the third part to its control. The last part presents preliminary results obtained for the wrist pronation/supination motion.